1. Field of the Invention
The present invention relates to a vehicle steering apparatus.
2. Description of Related Arts
In rack-and-pinion type steering apparatuses for automobiles, rack shafts are axially moved as a pinion is rotated to steer steering wheel. More specifically, tie rods are respectively connected through ball joints to both ends of a rack shaft supported by a housing. Consequently, each of the tie rods is moved as the rack shaft is axially moved, causing a knuckle arm connected to the tie rod to be rotated.
Generally, spacers are respectively mounted on both ends of a rack shaft. Each of the spacers is abutted on a stopper member made of a metal fixed to a housing at a final end position of a stroke of the rack shaft to regulate the movement of the rack shaft. Proposed as such a spacer is one having a metal annulus supported by a housing of a ball joint through an elastic portion and regulating the axial movement of the rack shaft by the metal annulus being abutted on a stopper member made of a metal (see Japanese Unexamined Utility Model Publication No. 5-54150 U published on Jul. 20, 1993, for example).
When the metal annulus in the spacer is abutted on the stopper member, however, noise due to a collision sound between metals may be produced. In order to reduce the collision sound, a spacer having a buffering section made of a rubber-like elastic material which is abutted on a stopper member provided on the outer periphery of a metal annuls before the metal annulus is abutted on the stopper member(see Japanese Unexamined Patent Publication No. 11-78914 published on Mar. 23, 1999, for example), a spacer having a plurality of recesses opened radially outward arranged in the circumferential direction provided on at least one of side surfaces of a metal annulus and having a buffering section composed of a rubber-like elastic member axially projecting farther than an end surface of the metal annulus in each of the recesses (see Japanese Unexamined Patent Publication No. 10-297504 published on Nov. 10, 1998, for example).
In the configurations exemplified in JP 11-78914 U and JP 10-297504 A, the buffering section tends to spread radially outward when collision with the stopper member. However, the radially outward deformation of the buffering section is not restricted. Therefore, the buffering section is not sufficiently axially compressed and deforms radically outward, so that a buffering effect required to reduce noise may not be reliably exhibited.
The present invention has been made under such a background to provide a steering apparatus that can reliably reduce noise.